1. Field of the Invention
The present invention relates in general to an injector, and particularly relates to an injector for freely presetting a dose.
2. Description of the Related Art
In the past, insulin injection is drawing drugs with the syringe then to carry out the injection. The procedure of drawing drugs is complication and hard to control the drawing dosage. Moreover, it is quit inconvenient for users to use many implements. Therefore, an insulin injector is designed for users to get more conveniently with insulin injection.
A conventional insulin injector needs to preset a dose before injection. To be noticed, when preset over a desired dose, it has to zeroing then reset the dose, and that is not convenient for users.
Further, there is usually a button in a posterior of the conventional insulin injector. When users pushed the button by mistake, the drug will leak from a needle of the insulin injector to cause an inaccuracy of injecting dose and even induce serious harm indirectly for users. Thus, a need exists for improved the device such as injector.